Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantas semanas existem?
 ###Tabelas: CREATE TABLE regular_season (regular_season_id AUTO_INCREMENT PRIMARY KEY, Week INT, Date VARCHAR, Opponent VARCHAR, Result VARCHAR, Game site VARCHAR, Record VARCHAR, Attendance INT) CREATE TABLE waitaki_district (waitaki_district_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Years VARCHAR, Gender VARCHAR, Area VARCHAR, Authority VARCHAR, Decile INT, Roll INT) CREATE TABLE first_round_thursday (first_round_thursday_id AUTO_INCREMENT PRIMARY KEY, Place VARCHAR, Player VARCHAR, Country VARCHAR, Score INT, To par VARCHAR) CREATE TABLE 2010_newcomers_race_'a'_practice_times_and_leaderboard (2010_newcomers_race_'a'_practice_times_and_leaderboard_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Rider VARCHAR, Sat 21 Aug VARCHAR, Mon 23 Aug VARCHAR, Tues 24 Aug VARCHAR, Wed 25 Aug VARCHAR, Thurs 26 Aug VARCHAR, Fri 27 Aug VARCHAR, Sat 28 Aug VARCHAR) CREATE TABLE typical_values_of_sfc_for_thrust_engines (typical_values_of_sfc_for_thrust_engines_id AUTO_INCREMENT PRIMARY KEY, Engine type VARCHAR, Scenario VARCHAR, SFC in lb/(lbf·h) INT, SFC in g/(kN·s) INT, Specific impulse (s) INT, Effective exhaust velocity (m/s) INT)  
SELECT MAX Week FROM regular_season